A puffed snack produced by using an extruder and using milled grains and flours as ingredients normally has the same nature and color tone in the surface layer and the inside without having any difference therebetween. This is mainly due to the ingredients, and hence the puffed snack is likely to be simple without having any individuality.
As the conventional apparatus for manufacturing a puffed snack, as shown in FIG. 11, there is known one in which a cutting blade D is installed so as to lightly touch the point face of a nozzle hole B provided at the point portion of an extruder A and driven by a motor M, to thereby cut the extruded dough (U.S. Pat. No. 5,435,714).
Further, there is known a manufacturing apparatus in which the dough extruded from a nozzle hole is drawn out by a drawing roll, a blade plate protruding radially or at a right angle with respect to the circumference of the drawing roll is fitted thereto, and the extrudate is made to pass through the drawing roll having the blade plate to thereby cut the extrudate at a right angle with respect to the extruding direction. However, neither of these apparatuses can manufacture a puffed snack having a different texture and color tone in the surface layer and the inside.
It is therefore an object of the present invention to provide a method and apparatus for manufacturing a puffed snack having an improved texture by making the surface layer hard and the inside soft, while giving a difference in color tone between the surface layer and the inside.